Mechanical calculators

My name is Kees Nagtegaal. I made this site for collectors of non-electric mechanical calculating devices.


My collection exists of over a hundred:  Seidel & Naumann

  • mechanical calculators (Odhner, Brunsviga, Facit),
  • adders (Addiator, Produx, Resulta, etc.),
  • adding machines (Comptometer, Burroughs, Plus, etc.),
  • counters (Durant, Record, Hengstler, etc.),
  • slide-rules (Aristo, Nestler,etc.),
  • and more.

You can see all of those with description in the gallery. Feel free to check out my books and manuals, too.

A few calculators and most of my slide-rules are for sale. If you would like to purchase items, please ask. If you have any nice object (and a nice price) for my collection, please contact me. I am very interested in addiators and other slide-adders.

If you are interested in Addiators, you can see here the catalogue Addiators and other slide adders.

If you want download or print this catalogue, you had to go to the page  Addiator Catalogue